| 摘要 |
PROBLEM TO BE SOLVED: To provide a check valve allowing accurate setting of set pressure for pressure relief.SOLUTION: A check valve includes: a sliding shaft 2 opposed to a flow channel primary side at its tip end; a packing 3 disposed on an outer periphery of the sliding shaft 2, and on a flow channel secondary side of a tip end of the sliding shaft 2; a first spring 4 disposed axially between the packing 3 and the sliding shaft 2; and a second spring 5 fixed in the axial direction of the sliding shaft 2, and disposed on the flow channel secondary side of the first spring 4. When pressure is applied from the flow channel secondary side so that the tip end of the sliding shaft 2 is separated from the packing 3, a flow channel 8 is formed between the packing 3 and the sliding shaft 2. Set pressure for pressure relief is determined by pressure difference between the flow channel primary side and secondary side applied to the sliding shaft 2, and force to press the packing 3 by the first spring 4, and is hardly affected by temperature characteristics and hardness of the packing 3, thereby allowing accurate setting for pressure relief. |
